Djokovic had tumbled down the rankings, slowed last year by an elbow injury and a loss of confidence that accompanied a 54-week title drought.

Since bursting out of the slump with an unexpected Wimbledon title he has gone from strength to strength, adding a long-awaited Cincinnati Masters title to his resume before adding the US Open title to those he won in 2011 and 2015.

Djokovic faced neither of his greatest rivals en route to the title in Flushing Meadows.

Seeded to face Federer in the quarter-finals, he found himself instead across the net from John Millman after the unheralded Australian stunned the Swiss great.

Nadal hobbled out of a semi-final match against Del Potro after two sets.

Djokovic would have relished taking on either — or both, although he admits that early in his career that wasn’t always the case.

“Maybe 10 years ago I would say I’m not so happy to be part of this era with Nadal and Federer,” he said.

“Today I really am. I feel like these guys, rivalries with these guys, matches with Federer and Nadal, have made me the player I am, have shaped me into the player I am today.

“I owe it to them.”

Although he was riding high coming into the Open, Djokovic was among the many struggling with crushing heat and humidity in the first week.

He needed four sets to get past 41st-ranked Hungarian Marton Fucsovics in the first round and another to get past 61st-ranked American Tennys Sandgren in the second.

‘Ole Nole’

He picked up the pace with straight-sets victories over France’s Richard Gasquet, Portugal’s Joao Sousa, Millman and 2014 finalist Kei Nishikori to arrive at a title tilt with good friend Del Potro.

After seizing an early break in the second set, Djokovic suddenly found himself on the run, dropping three straight games before he dug in to salvage a service hold in a 20-minute marathon game that went to deuce eight times.

The crowd was roaring for sentimental favorite Del Potro — shut out of Grand Slam finals since his 2009 US Open triumph.

Djokovic said it was the kind of heavyweight clash he’s learned to embrace.

“This might sound funny, but my nickname is Nole. When they shout “Ole, ole, ole, ole,” that’s what I hear,” he said of the raucous chants for Del Potro.

“I thought it was electrifying in some stages of the match, especially in the second set when we went toe-to-toe. I had my corner, as well.

“When the roof is closed, trust me, it’s very, very loud down there. It takes a lot of effort to actually stay poised in this moment.